Cardiac biomarkers have been used since the 1950s to detect and monitor myocardial injury. Common biomarkers include cardiac enzymes like CK-MB and LDH that rise within 1-2 days of injury. More specific markers like cardiac troponins rise later at 2-3 hours and persist for up to 10 days, making them more useful for detecting minor injuries. Newer inflammatory markers may provide additional prognostic information but require more standardization. A variety of cellular and matrix proteins also reflect the extent of injury and repair.

1. Cardiac Bio Markers

2. –“A biomarker is a substance used as an
indicator of a biologic state”.
– Accurate repeated measurements at
reasonable cost
– Must provide additional information
– Should aid treatment

3. HISTORY OF CARDIAC BIOMARKERS
• 1954 - SGOT (AST)
• 1955 - LDH
• 1960 - CPK
• 1972 - CPK isoforms by Electrophoresis
• 1975 - CK - MB by immunoinhibition
• 1975 - Myoglobin
• 1985 - CK - MB Mass immunoassay
• 1989 - Troponin T
• 1992 - Troponin I
3

4. CLASSIFICATION OF CARDIAC
BIOMARKERS
• Biomarkers of myocardial injury
– markers of myocardial necrosis
– markers of myocardial ischemia
• Biomarkers of haemodynamic stress
• Inflammatory and prognostic Biomarkers
4

5. 5

6. Marker for
inflammation
hsCRP sCD40L Homocysteine
Marker for plaque
Destabilization
PAPP-A LP-PLA2
Marker for
hemodynamic
stress
Natriuretic peptides
• ANP
• BNP
• Pro-BNP
• CNP

7. LDH
• Pyruvate  lactate
• 100-200 U/L
• Concentration in RBC is high than plasma
• 5 iso enzmes
• Flipped pattern
• Increases by 24-48 hours
• Peak in 3-6 days
• Normalises in 8-14 days

10. Aspartate aminotransferase
(AST,SGOT)
• 8-20 u/l
• Raise by 6–8 h
• peak by 18–24 h,
• Normalises by 4 to 5 d

11. CREATINE KINASE
Function: it catalyses the conversion of creatine to
phosphocreatine degrading ATP to ADP
• The CK enzyme consists of two subunits, B (brain type) or M
(muscle type), Making three different isoenzymes: CK-MM,
CK-BB and CK-MB
• CK-BB occurs mainly in tissues, rarely of any significance in the
bloodstream
• Skeletal muscle expresses CK-MM (98%) and low levels of CK-
MB (1%)
• The myocardium has CK-MM at 70% and CK-MB at ~30%
11

12. CK-MB
• High specificity for cardiac tissue
• Begins to rise 4-6 hours after onset of infarction
• Peaks at about 12 hours
• Returns to baseline at 24-36 hours
• Can be used to indicate early re-infarction if level normalizes
and then increases again
12

15. DETECTION
• The CK-MB isoforms may also be analyzed using high-
voltage electrophoresis
• The ratio of MB2/MB1 is calculated
• MB2 released from heart muscle and converted to MB1
• A level of MB2 > or = 1 and a ratio of MB2/MB1 > 1.5
indicates myocardial injury
• A result is positive if MB2 is elevated and the ratio is more
than 1.5
15

16. • False positive (for MI) CK-MB elevation can be seen
in:
– Significant skeletal muscle injury
– The MB fraction is determined to be expressed
during the process of muscle regeneration
– Cardiac injury for reason other than MI
• Defibrillation
• Blunt chest trauma
• Cocaine abuse
16

17. MYOGLOBIN
• Small-size heme protein found in all tissues mainly assists in
oxygen transport
• It is released from all damaged tissues
• Increases often occur more rapidly than TI and CK
• Released from damaged tissue within 1 hour
• Normal value: 17.4-105.7 ng/ml
• Timing:
– Earliest Rise: 1-3 hrs
– Peak 6-9 hrs
– Return to normal: 12 hrs 17

18. CONDITIONS FOR MYOGLOBIN INCREASE
• Acute myocardial infarction
• Skeletal muscle damage, muscular dystrophy,
inflammatory myopathies
• Renal failure, severe uremia
• Shock and trauma
18

19. • Rapid monitor of success of thrombolytic therapy
• Negative predictor of MI
• Due to poor specificity, myoglobin levels do not
always predict myocardial injury
• Not utilized often for AMI/cardiac damage
assessment because of its very rapid metabolism
19

20. CARDIAC TROPONINS
• Troponin is a complex of three regulatory proteins that is
integral to non-smooth muscle contraction in skeletal as well
as cardiac muscle
• Troponin is attached to the tropomyosin sitting in the groove
between actin filaments in muscle tissue
• Troponin has three subunits, TnC, TnT, and TnI
– Troponin-C has calcium binding ability and has no
diagnostic value
– Troponin-T binds the troponin tropomyosin complex,
– Troponin-I is an inhibitory protein
20

21. 21

22. Cardiac Troponin Release after MI
22

23. TROPONIN I
1. Cardiac Troponin I (cTnl) is a cardiac muscle protein with a
molecular weight of 24 kilo-Daltons.
2. The cTnl has a additional amino acid residues on its N-
terminal that are not exist on the skeletal form.
3. The half life = 2~4 hours.
4. Serum increase = 2-8 hours
23

24. TROPONIN T
1. Cardiac Troponin T (cTnT) is present in fetal
skeletal muscle.
2. In healthy adult skeletal muscle cTnT is absent.
3. The gene of cTnT may be re-expressed in
skeletal muscle disease.
4. Biological half life and early serum increases of
cTnT are similar to that of cTnI.
24

25. TROPONIN LEVELS
• Less than 5% in cytosol
• Troponin levels begin to rise 2-3 hours after onset of myocardial injury
• Elevations in Troponin-I and Troponin-T can persist for up to 10 days
after MI
• CK-MB returns to baseline by 48 hours
• Thus far, studies have failed to find a source of Troponin-I outside the
heart, but have found some Troponin-T in skeletal muscle
25

26. Conditions commonly associated with cardiac troponin elevations
• Arrhythmias
• Congestive heart failure
• Coronary artery disease
• Coronary vasospasm
• Critically ill patient
• Hypertension
• Myocarditis
• Pericarditis
• Pulmonary embolism
• Pulmonary hypertension, severe
• Renal failure
• Sepsis/septic shock
• Sepsis-related myocardial dysfunction
• Systemic inflammatory diseases
• Trauma
26

27. Increased Troponins
• Troponin T and I are not detected in healthy individuals
• Significant increase in Troponins reflects myocardial
necrosis
• ACC/ESC has defined increase in Troponins as a
measurement above 99th percentile value of reference
group
• To reduce false-positive outcomes, CV of 10% at decision
limit is recommended
27

28. TROPONIN ASSAYS
• TropT (Roche Diagnostics, Germany)
• Trop I (Siemens Healthcare Diagnostics)
• Troponin T
– 99th percentile limits - 0.01 ng/mL
– assay ranges - 0.01-25 ng/mL
• (Troponin I)
– 99th percentile limits -0.04 ng/mL
– assay range -0.04-40 ng/mL
• Reference limits based on the 99th percentile for a healthy
population are 0.01 ng/mL (Troponin T) and 0.04 ng/mL (Troponin I)
28

29. Timing Summary
TEST ONSET PEAK DURATION
CK/CK-MB 4-8 hours 18-24 hours 36-48 hours
Troponins 3-12 hours 18-24 hours Up to 10 days
Myoglobin 1-4 hours 6-7 hours 24 hours
LDH 6-12 hours 24-48 hours 6-8 days

30. Ischemia Modified Albumin (IMA)
• A novel marker of ischemia, is produced when circulating serum
albumin contacts ischemic heart tissues
• IMA can be measured by the albumin cobalt binding (ACB) assay
that is based on IMA's inability to bind to cobalt
• Mechanism- due to structural change in the amino terminal end of
albumin
• IMA levels rise within 6 hours
• Remains elevated for 12 hours
30

31. • IMA levels raised in non- cardiac ischemia
• Modification to n- terminal end may also
be induced by extracellular hypoxia,
acidosis etc,
• FDA in 2010 has approved a multimarker
approach for using the combination of
ECG, the cTnI, and the IMA levels
achieving a sensitivity of 95% for ACS
31

32. Heart-type fatty acid binding protein (H-FABP)
• H-FABP is a very stable abundant [138] low molecularweight protein (14–15
kDa) in the cytoplasm of myocardial cells
• Appearing as early as 90 min after symptom onset and peaking within 6 h
• Parameters of kinetic release make it an ideal candidate both for early
assessment or exclusion of AMI and for the measurement of a recurrent
infarction
32

33. • A study by Puls et al
– the negative predictive value (NPV) of H-FABP was an
impressive 100%
– its Positive predictive value was 41% which was greater
than that of both cTnT (29%) and NT-proBNP (19%).
• The myoglobin/heart FABP ratio has been used to
differentiate between heart muscle and skeletal muscle injury
33

34. • The NP family includes
ANP : -atrial natriuretic peptide (28 a.a.)
N-terminal proANP (98 a.a.)
BNP : brain natriuretic peptide (32 a.a.)
N-terminal proBNP (76 a.a.)
CNP : C-type natriuretic peptide (22 and 53 a.a.)
34

35. NATRIURETIC PEPTIDES
• ANP is released primarily in response to atrial wall
stretching and intravascular volume expansion.
• BNP is mainly secreted by the ventricles
• CNP is found predominantly in the brain and also
synthesized by vascular endothelial cells
35

36. N-terminal proBNP interpretation in the patients with acute
dyspnea without severe renal failure

37. Stefan Blankenberg, MD; Renate Schnabel, MD; Edith Lubos, MD, et al., Myeloperoxidase Early Indicator of Acute Coronary Syndrome and
Predictor of Future Cardiovascular Events 2005
37

38. sCD40 Ligand
• CD40 ligand is a transmembrane protein related
to TNF.
• It has multiple prothrombotic and proatherogenic
effects.
• What is usually measured is the soluble form of
the receptor, sCD40 ligand, which has been
shown to be a predictor of events after acute
presentation.
• At present, standardized assays, reference
interval studies, nor consistent assay validations
are not available.
38

39. Serum Amyloid Protein A
• Serum amyloid protein A, an acute-phase
protein and an apolipoprotein, has been used
with hsCRP in cross-sectional studies.
• It can be synergistic with hsCRP326 but is
much less commonly used.
• At present, no standardized assays, reference
interval studies, nor consistent assay
validations are available.
39

40. Cytokines
• A variety of stimulatory and inhibitory interleukins
(TNF, IL-1, IL-6, IL-8, IL-12, IL-18) are thought to help
mediate the elaboration of CRP and the development
of atherosclerosis and acute events.121 These
cytokines may stimulate or inhibit leukocytes, often
through T cell–mediated processes and effects on
monocytes, which are indigenous to atherogenesis.
• In some studies, IL-6 is more prognostic than hsCRP.
• These cytokines often have inhibitors and/or binding
proteins that modulate their effects. At present,
standardized assays, reference intervals studies, and
consistent assay validations are not available.
40

41. Lipoprotein-Associated Phospholipase
A2
• Phospholipase A2 (Lp-PLA2) is a phospholipase associated
with LDL that is thought to be an inflammatory marker.
• It was previously known as platelet-activating factor (PAF)
acetyl hydrolase.
• It is synthesized by monocytes and lymphocytes and is
thought to cleave oxidized lipids to produce lipid fragments
that are more atherogenic and that increase endothelial
adhesion.
• An FDA-approved assay for this analyte includes obligatory
reference intervals.
• It has been shown to be predictive of events in a primary
prevention cohort, even when hsCRP is present in the
model, suggesting that it measures something different
from what is measured by the acute-phase reactants
associated with hsCRP. 41

42. Pregnancy-Associated Plasma Protein
A
• Pregnancy-associated plasma protein A (PAPP-A) is a
metalloproteinase that is thought to be expressed in
plaques that may be prone to rupture.
• The literature in this regard is mixed at present
concerning its use.
• At present, standardize assays, reference interval
studies, and consistent assay validations are not
available.
• Recent data suggest that heparin administration in MI
patients is associated with increased PAPP-A
concentrations; this may limit its prognostic role.
42

43. Oxidized LDL
• Oxidized LDL has been attributed a key role in the
development of atherosclerosis.
• Several methods have been used to measure it,
but they yield potentially different data.
• Some have correlated malondialdehyde LDL with
the development of atherosclerosis and short-
term events.
• Direct identification with antibodies suggests that
oxidized LDL may be released from vessels and
may colocalize with lipoprotein a [Lp(a)] after
acute events.
43

44. Placental Growth Factor
• Placental growth factor is an angiogenic factor
related to vascular endothelial growth factor
(VEGF), which stimulates smooth muscle cells and
macrophages.
• It also increases TNF and MCP-1. A novel assay
for this analyte is thought to provide additional
prognostic information on patients who present
with ACS.
• At present, standardized assays, reference
interval studies, and consistent assay validations
are not available.
44

45. Matrix Metalloproteinases
• Matrix metalloproteinases (MMPs) can degrade the collagen matrix
in coronary artery or myocardium.
• They are integral to remodeling of the coronary artery and/or the
heart after acute events.
• Elaboration of MMP-9, a gelatinase, is thought to be important in
plaque destabilization; thus some have tried to measure it as a
prognostic index.
• Other MMPs participate in the elaboration of extracellular matrix in
the heart.
• Many MMPs also have inhibitors [tissue inhibitors of
metalloproteinase (TIMPs)] that modulate their effects.
• At present, standardized assays, reference intervals studies, and
• consistent assay validations are not available.
45

46. Monocyte Chemotactic Protein
• Monocyte chemotactic protein (MCP-1) is a
chemokine that is thought to be responsible for
the recruitment of monocytes into
atherosclerotic plaque.
• It has been reported to be elevated in patients
with ACS and to have long-term predictive value.
• However, at present, standardized assays,
reference interval studies, and consistent assay
validations are not available
46

47. Tissue Plasminogen Activator Antigen (t-PA) and
Plasminogen Activator Inhibitor 1 (PAI-1)
• t-PA is the body’s physiologic fibrinolytic activator.
• PAI-1, its endogenous inhibitor, binds to t-PA.
• Inhibition of fibrinolysis has been suggested to be a
reason for recurrent infarction; the fact that maximal
inhibition usually occurs in the early morning hours
provides a potential explanation for the circadian
variability of AMI.
• It may also be the reason why persons with diabetes
have such unstable disease; the growth factor
properties of insulin stimulate increases in PAI-1.
• An accurate assessment of this system includes both t-
PA and PAI-1, along with some assessment of bound
versus free levels.
47

48. Secreted Platelet Granular Substances
• Both platelet factor 4 (PF4) and beta thromboglobulin
(BTG) are secreted when platelets aggregate.
• PF4 has a short half-life and is released by heparin.
• BTG is not released by heparin and has a longer half-
life.
• Both markers have been used to assess platelet
aggregation.
• BTG is by far the more reliable.
• At present, standardized assays, reference interval
studies, and consistent assay validations are not
available.
48

49. Unbound Free Fatty Acid
• Unbound free fatty acid (uFFA)39 has also
been touted as a marker of ischemia.
• Most fatty acid is bound, and ischemia is
thought to increase the small unbound
fraction.
• Initial studies have reported mixed results.
• At present, standardized assays, reference
interval studies, and consistent assay
validations are not available.
49

50. Nourin
• Nourin I is a small protein released rapidly by
“stressed myocytes.”
• It induces changes in a variety of inflammatory
cytokines and attracts neutrophils.
• Preliminary studies have been done to
attempt to validate its use.
• At present, standardized assays, reference
interval studies, and consistent assay
validations are not available.
50

51. Copeptin
• Copeptin, a 30 amino acid glycoprotein constituting the
C-terminal portion of arginine vasopressin, has been
shown to be a prognostic biomarker in hemorrhagic
and septic sepsis.
• More recently, data have shown that measurement of
copeptin serves as a rapid and early rule-out biomarker
for AMI at presentation in patients with symptoms
suggestive of ACS with a normal cTn value.
• An assay measuring copeptin (CT-proAVP) has been
described using the Brahms Kryptor Immunology
Analyzer, Diamond Diagnostics Holliston, MA.
• Additional clinical and analytical validation studies will
be necessary, especially head-to-head comparisons of
copeptin versus the new hs-cTn assays.
51